Control system for automatic transmission and method thereof

ABSTRACT

The control system for an automatic transmission may include, a detecting portion of driving information adapted to detect the driving information including a temperature of an engine coolant, temperature of a transmission oil, a positional change of an accelerator pedal, a current shift-speed, and driving speed. a control portion adapted to determine a virtual positional change of the accelerator pedal based on an actual positional change of the accelerator pedal and a tip-in speed transmitted from the detecting portion of driving information, to determine a target shift-speed according to the actual positional change of the accelerator pedal or the virtual positional change of the accelerator pedal and the driving speed, and to control a shift to the target shift-speed. an actuator adapted to engage the target shift-speed according to a control signal received from the control portion.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No.10-2011-0105436 filed in the Korean Intellectual Property Office on Oct.14, 2011, the entire contents of which is incorporated herein for allpurposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a control system for an automatictransmission and a method thereof. More particularly, the presentinvention relates to a control system for an automatic transmission anda method thereof that can provide shift-speed control improvingacceleration responsiveness by determining a virtual positional changeof an accelerator pedal V_(APS) containing an acceleration intentionfrom a positional change of the accelerator pedal ΔAPS due to tip-in anda tip-in speed.

2. Description of Related Art

An automatic transmission includes a friction element, a state of whichis changed from engagement to release and another friction element, astate of which is changed from release to engagement according to ashift control of a vehicle. Operations of the friction elements arecontrolled by hydraulic pressure. In addition, because performance ofthe automatic transmission is influenced by engagement or release timingof the friction elements, research has been carried out so as to improveshift performance further.

The automatic transmission includes a transmission control unit (TCU)for controlling the shift, and the transmission control unit determinesa target shift-speed from a predetermined shift pattern map according toa driving speed and a positional change of an accelerator pedal(throttle valve opening). After the target shift-speed is determined,the transmission control unit controls the hydraulic pressure through anactuator (solenoid valve) such that an on-coming friction element is tobe engaged and an off-going friction element is to be released.Therefore, the shift to the target shift-speed is controlled.

Because the predetermined shift pattern map of the automatictransmission is set so as to improve fuel economy, accelerationresponsiveness may be deteriorated.

In addition, if the positional change of the accelerator pedal accordingto tip-in is within a reference range of upshift/downshift of the shiftpattern map, the shift is not influenced by the positional change of theaccelerator pedal. Therefore, upshift or downshift is not performed anda current shift-speed is maintained.

At this time, engine output rises and vehicle speed increases by thetip-in of the accelerator pedal. Because the shift-speed does notchange, the vehicle speed increases only by the engine output and thusacceleration responsiveness may be deteriorated, however.

For example, FIG. 6 illustrates a case where the positional change ofthe accelerator pedal occurs by the tip-in but the shift-speed does notchange in a state of a seventh forward speed. That is, because thepositional change of the accelerator pedal is within the reference rangeof upshift/downshift of the shift pattern map, the shift-speed ismaintained to be the seventh forward speed that is a currentshift-speed. In this case, the vehicle speed increases due to increaseof the engine output.

Since the shift-speed, however, does not change, the vehicle speedchanges slowly. Therefore, acceleration responsiveness may beinsufficiently provided compared with acceleration intention of a driveraccording to the tip-in.

The information disclosed in this Background of the Invention section isonly for enhancement of understanding of the general background of theinvention and should not be taken as an acknowledgement or any form ofsuggestion that this information forms the prior art already known to aperson skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing acontrol system for an automatic transmission and a method thereof havingadvantages of improving acceleration responsiveness according to atip-in speed by providing a first shift pattern map for determining atarget shift-speed based on an actual positional change ΔAPS of anaccelerator pedal and a driving speed and a second shift pattern map fordetermining a target shift-speed based on a virtual positional changeVAPS of the accelerator pedal determined according to the actualpositional change ΔAPS of the accelerator pedal and a tip-in speed(%/sec) and the driving speed.

In addition, a control system for an automatic transmission and a methodthereof are provided according to an exemplary embodiment of the presentinvention, wherein the virtual positional change VAPS of the acceleratorpedal determined according to the actual positional change of theaccelerator pedal and the tip-in speed is adapted to containacceleration intention of a driver. Since different target shift-speedscan be determined though the actual positional changes of theaccelerator pedal are the same, acceleration performance may beimproved.

In addition, a control system for an automatic transmission and a methodthereof that return to a shift control at which the first shift patternmap is used after improving the acceleration responsiveness through adownshift performed based on the virtual positional change VAPS of theaccelerator pedal containing the acceleration intention of the driverand determined according to the actual positional change of theaccelerator pedal and the tip-in speed.

A control system for an automatic transmission according to an exemplaryembodiment of the present invention may include, a detecting portion ofdriving information adapted to detect the driving information includinga temperature of an engine coolant, temperature of a transmission oil, apositional change of an accelerator pedal, a current shift-speed, anddriving speed. a control portion adapted to determine a virtualpositional change of the accelerator pedal based on an actual positionalchange of the accelerator pedal and a tip-in speed transmitted from thedetecting portion of driving information, to determine a targetshift-speed according to the actual positional change of the acceleratorpedal or the virtual positional change of the accelerator pedal and thedriving speed, and to control a shift to the target shift-speed. anactuator adapted to engage the target shift-speed according to a controlsignal received from the control portion.

The control system may further include a memory portion storing a map inwhich the virtual positional change of the accelerator pedal accordingto the actual positional change of the accelerator pedal and the tip-inspeed is set, a first shift pattern map in which the target shift-speedaccording to the actual positional change of the accelerator pedal andthe driving speed is set, and a second shift pattern map in which thetarget shift-speed according to the virtual positional change of theaccelerator pedal and the driving speed is set.

The control portion may be adapted to detect the actual positionalchange of the accelerator pedal and the tip-in speed in a case that thecoolant temperature exists within a predetermined first temperaturerange, the oil temperature exists within a predetermined secondtemperature range, and the current shift-speed is higher than or equalto a third forward speed.

The control portion may be adapted to perform a shift control byapplying the second shift pattern map in a case that the actualpositional change of the accelerator pedal due to tip-in is greater thanor equal to a predetermined first positional change and the tip-in speedis faster than or equal to a predetermined speed.

The control portion may be adapted to perform a shift control byapplying the first shift pattern map in a case that the actualpositional change of the accelerator pedal due to tip-in is smaller thana predetermined first positional change or the tip-in speed is slowerthan a predetermined speed.

The control portion may be adapted to downshift to the targetshift-speed so as to improve acceleration responsiveness due to a highengine output and a low gear ratio when the shift is controlled byapplying the second shift pattern map.

The control portion may be adapted to limit the virtual positionalchange of the accelerator pedal according to the actual positionalchange of the accelerator pedal and the tip-in speed such that thevirtual positional change of the accelerator pedal does not exceed theactual positional change of the accelerator pedal by a limiting amount.

The control portion may be adapted to perform the shift control byapplying the first shift pattern map when a predetermined releasecondition is satisfied in a state of performing the shift control byapplying the second shift pattern map.

The predetermined release condition may be satisfied when the actualpositional change of the accelerator pedal is smaller than or equal to apredetermined second positional change, a predetermined time has passedafter downshifting to the target shift-speed, or a predeterminedshift-speed is engaged.

A control method for an automatic transmission according to anotherexemplary embodiment of the present invention may include, determiningwhether a first condition is satisfied from driving information.determining, when the first condition is satisfied, whether an actualpositional change of an accelerator pedal due to tip-in and a tip-inspeed satisfies a second condition. determining a virtual positionalchange of the accelerator pedal according to the actual positionalchange of the accelerator pedal and the tip-in speed when the secondcondition is satisfied. determining a target shift-speed according tothe virtual positional change of the accelerator pedal and a drivingspeed. controlling a shift to the target shift-speed according to thevirtual positional change of the accelerator pedal and the drivingspeed.

If a predetermined release condition is satisfied in a state ofcontrolling the shift to the target shift-speed according to the virtualpositional change of the accelerator pedal and the driving speed, ashift to a target shift-speed according to the actual positional changeof the accelerator pedal and the driving speed may be controlled.

The first condition may be satisfied when a coolant temperature existswithin a predetermined first temperature range, an oil temperatureexists within a predetermined second temperature range, and a currentshift-speed is higher than or equal to a third forward speed.

The second condition may be satisfied when the actual positional changeof the accelerator pedal due to the tip-in is greater than or equal to apredetermined first positional change and the tip-in speed is fasterthan or equal to a predetermined speed.

The target shift-speed according to the virtual positional change of theaccelerator pedal and the driving speed may be determined to be a lowershift-speed than the current shift-speed.

The virtual positional change of the accelerator pedal determined basedon the actual positional change of the accelerator pedal and the tip-inspeed does not exceed the actual positional change of the acceleratorpedal by a limiting amount.

The predetermined release condition may be satisfied when the actualpositional change of the accelerator pedal is smaller than or equal to apredetermined second positional change, a predetermined time has passedafter shifting to the target shift-speed according to the virtualpositional change of the accelerator pedal and the driving speed, or apredetermined shift-speed is engaged.

A control system for an automatic transmission according to otherexemplary embodiment of the present invention may include, a detectingportion of driving information adapted to detect the driving informationincluding a temperature of an engine coolant, temperature of atransmission oil, a positional change of an accelerator pedal, a currentshift-speed, and driving speed. a control portion adapted to control ashift of the automatic transmission based on the driving informationdetected by the detecting portion of driving information, wherein thecontrol portion determines whether a shift control is possible, andselectively performs fuel economy-oriented shift control according to anactual positional change of the accelerator pedal and the driving speedor acceleration-oriented shift control according to a virtual positionalchange of the accelerator pedal and the driving speed if the shiftcontrol is possible.

The virtual positional change of the accelerator pedal may be determinedaccording to the actual positional change of the accelerator pedal and atip-in speed.

The virtual positional change of the accelerator pedal does not exceedthe actual positional change of the accelerator pedal by a limitingamount.

The control portion may be adapted to perform the fuel economy-orientedshift control when a predetermined release condition is satisfied in astate of performing the acceleration-oriented shift control.

The methods and apparatuses of the present invention have other featuresand advantages which will be apparent from or are set forth in moredetail in the accompanying drawings, which are incorporated herein, andthe following Detailed Description, which together serve to explaincertain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a control system for an automatictransmission according to an exemplary embodiment of the presentinvention.

FIG. 2 is a flowchart of a control method for an automatic transmissionaccording to an exemplary embodiment of the present invention.

FIG. 3 is a schematic diagram for showing an example of a shift patternmap applied to a control system for an automatic transmission accordingto an exemplary embodiment of the present invention.

FIG. 4 and FIG. 5 are graphs for showing shift states when a virtualpositional change of an accelerator pedal is applied to a control methodfor an automatic transmission according to an exemplary embodiment ofthe present invention.

FIG. 6 is a schematic diagram for showing acceleration responseaccording to a positional change of an accelerator pedal in aconventional automatic transmission.

It should be understood that the appended drawings are not necessarilyto scale, presenting a somewhat simplified representation of variousfeatures illustrative of the basic principles of the invention. Thespecific design features of the present invention as disclosed herein,including, for example, specific dimensions, orientations, locations,and shapes will be determined in part by the particular intendedapplication and use environment.

In the figures, reference numbers refer to the same or equivalent partsof the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of thepresent invention(s), examples of which are illustrated in theaccompanying drawings and described below. While the invention(s) willbe described in conjunction with exemplary embodiments, it will beunderstood that the present description is not intended to limit theinvention(s) to those exemplary embodiments. On the contrary, theinvention(s) is/are intended to cover not only the exemplaryembodiments, but also various alternatives, modifications, equivalentsand other embodiments, which may be included within the spirit and scopeof the invention as defined by the appended claims.

The present invention will be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown.

As those skilled in the art would realize, the described embodiments maybe modified in various different ways, without departing from the spiritor scope of the present invention. Description of components that arenot necessary for explaining the present invention will be omitted.

FIG. 1 is a block diagram of a control system for an automatictransmission according to an exemplary embodiment of the presentinvention.

As shown in FIG. 1, an exemplary embodiment of the present inventionincludes a detecting portion 100 of driving information, a controlportion 200, a memory portion 300, and an actuator 400.

The detecting portion 100 of driving information detects drivinginformation during running of a vehicle to which an automatictransmission according to an exemplary embodiment of the presentinvention is applied, and transmits information corresponding thereto tothe control portion 200.

The detecting portion 100 of driving information may include a coolanttemperature detector 101, an oil temperature detector 102, anaccelerator pedal position detector 103, a shift-speed detector 104, anda vehicle speed detector 105.

The coolant temperature detector 101 detects a temperature of a coolantcirculating through an engine, and transmits information correspondingthereto to the control portion 200.

The oil temperature detector 102 detects a temperature of an oil thatoperates friction elements including clutches and brakes of theautomatic transmission, and transmits information corresponding theretoto the control portion 200.

The accelerator pedal position detector 103 detects a positional changeΔAPS of an accelerator pedal and a tip-in speed (%/sec) according totip-in by a driver, and transmits information corresponding thereto tothe control portion 200. An accelerator position sensor (APS) can beused as the accelerator pedal position detector 103.

The shift-speed detector 104 detects a current shift-speed that isengaged according to a driving speed and the positional change of theaccelerator pedal, and transmits information corresponding thereto tothe control portion 200.

The vehicle speed detector 105 detects a current driving speed, andtransmits information corresponding thereto to the control portion 200.

The control portion 200 determines a target shift-speed according to thedriving speed and the positional change of the accelerator pedalreceived from the detecting portion 100 of driving information by usinga first shift pattern map stored in the memory portion 300, and controlsthe actuator 400 according to the determined target shift-speed so as toperform a shift control to the target shift-speed.

If the information received from the detecting portion 100 of drivinginformation satisfies a first condition, the control portion 200 detectsthe positional change ΔAPS of the accelerator pedal according to thetip-in and the tip-in speed (%/sec) and determines whether a secondcondition is satisfied.

The first condition is satisfied when the coolant temperature detectedby the coolant temperature detector 101 exists within a predeterminedfirst temperature range (a temperature range where it can be determinedthat warm-up of the engine is completed), the temperature of anautomatic transmission oil detected by the oil temperature detector 102exists within a predetermined second temperature range (a temperaturerange where it can be determined that the oil is sufficientlyactivated), and the current shift-speed detected by the shift-speeddetector 104 is higher than or equal to a third forward speed.

In addition, the first condition further includes that system error isnot detected and error in CAN communication is not detected.

Herein, the first condition means a condition where the control portion200 can control a shift.

In addition, the second condition is satisfied when the positionalchange ΔAPS of the accelerator pedal according to the tip-in is greaterthan or equal to a predetermined first positional change (%) and thetip-in speed (%/sec) is faster than or equal to a predetermined speed.

The predetermined first positional change may be 10% but can be changeddepending on design scheme.

In addition, the predetermined speed, for example, may be 53%/sec butcan be changed depending on design scheme.

Herein, the second condition means a condition where the control portion200 controls the shift so as to improve acceleration responsiveness.

If the information received from the detecting portion 100 of drivinginformation satisfies the first condition and the second condition, thecontrol portion 200 determines a virtual positional change VAPS of theaccelerator pedal according to the positional change ΔAPS of theaccelerator pedal and the tip-in speed (%/sec) by using a map stored inthe memory portion 300. That is, the virtual positional change VAPS ofthe accelerator pedal contains acceleration intention of the driver.

In addition, the control portion 200 determines the target shift-speedby using a second shift pattern map according to the virtual positionalchange VAPS of the accelerator pedal stored in the memory portion 300,and controls the shift through the actuator 400. In this case, thecontrol portion 200 can improve the acceleration responsiveness byperforming a downshift.

If a predetermined release condition is satisfied after the controlportion 200 performs the downshift by applying the second shift patternmap according to the virtual positional change VAPS of the acceleratorpedal containing the acceleration intention and determined from thepositional change ΔAPS of the accelerator pedal and the tip-in speed,the control portion 200 performs the shift control by using the firstshift pattern map to which the actual positional change ΔAPS of theaccelerator pedal is applied so as to enhance fuel economy.

The release condition is satisfied when the positional change ΔAPS ofthe accelerator pedal is smaller than or equal to a predetermined secondpositional change (%), for example 10%, a predetermined time has passedafter downshifting by using the second shift pattern map according tothe virtual positional change VAPS of the accelerator pedal, or apredetermined shift-speed is engaged.

The control portion 200 is adapted to limit the virtual positionalchange VAPS of the accelerator pedal according to the positional changeΔAPS of the accelerator pedal and the tip-in speed (%/sec) such that thevirtual positional change VAPS of the accelerator pedal does not exceedthe actual positional change of the accelerator pedal ΔAPS by a limitingamount (%).

The limiting amount may be 35% but can be changed depending on designscheme.

The map at which the virtual positional change VAPS of the acceleratorpedal according to the positional change ΔAPS of the accelerator pedaland the tip-in speed (%/sec) is set is stored in the memory portion 300.

The first shift pattern map at which the target shift-speed according tothe actual positional change of the accelerator pedal APS and thedriving speed is set and the second shift pattern map at which thetarget shift-speed according to the virtual positional change VAPS ofthe accelerator pedal and the driving speed is set are stored in thememory portion 300.

An eight-speed shift pattern map according to the virtual positionalchange VAPS of the accelerator pedal stored in the memory portion 300,for example, are shown in FIG. 3.

The second shift pattern map according to the virtual positional changeVAPS of the accelerator pedal stored in the memory portion 300 isadapted to determine the target shift-speed for improving theacceleration responsiveness in a state that the positional change ΔAPSof the accelerator pedal according to the tip-in is greater than orequal to the first positional change (e.g., 10%) and the currentshift-speed is higher than or equal to the third forward speed.

The virtual positional change VAPS of the accelerator pedal stored inthe memory portion 300 may be limited so as not to exceed the actualpositional change of the accelerator pedal APS by the limiting amount(%).

The limiting amount, for example, may be 35%, but can be changeddepending on vehicle models and design scheme.

The actuator 400 includes at least one solenoid valve operating frictionelements including clutches and brakes, and is adapted to engage thetarget shift-speed according to a control signal of the control portion200.

Hereinafter, a control method for an automatic transmission according toan exemplary embodiment of the present invention will be described indetail with reference to the accompanying drawings.

In the automatic transmission according to an exemplary embodiment ofthe present invention, a shift control according to the actualpositional change of the accelerator pedal and the driving speed issimilar to a conventional shift control. Therefore, detailed descriptionof the shift control according to the actual positional change of theaccelerator pedal and the driving speed will be omitted.

If the vehicle in which the automatic transmission according to anexemplary embodiment of the present invention is used runs, thedetecting portion 100 of driving information detects the drivinginformation at a step S101 and transmits the driving information to thecontrol portion 200.

The information transmitted from the detecting portion 100 of drivinginformation to the control portion 200 includes the temperature of thecoolant circulating through the engine, the temperature of the oiloperating the friction elements including the clutches and the brakes,the current positional change (i.e., position) of the accelerator pedal,the current shift-speed engaged according to the driving speed and thepositional change of the accelerator pedal, and the driving speed.

At this time, the control portion 200 analyses the informationtransmitted from the detecting portion 100 of driving information anddetermines whether the first condition is satisfied at a step S102.

The first condition is satisfied when the coolant temperature existswithin the predetermined first temperature range, the oil temperatureexists within the predetermined second temperature range, and thecurrent shift-speed is higher than or equal to the third forward speed.

In addition, the first condition further includes that system error isnot detected and error in CAN communication is not detected.

If the first condition is not satisfied at the step S102, the controlportion 200 returns to the step S101.

That is, the control portion 200 determines that the first condition isnot satisfied if the coolant temperature does not exist within the firsttemperature range, the oil temperature does not exist within the secondtemperature range, or the shift-speed is lower than the third forwardspeed.

The first condition, however, is satisfied at the step S102, the controlportion 200 detects the positional change ΔAPS of the accelerator pedalaccording to the tip-in from the accelerator pedal position detector 103of the detecting portion 100 of driving information at a step S103 anddetects the tip-in speed (%/sec) at a step S104. After that, the controlportion 200 determines whether the second condition is satisfied basedon the positional change ΔAPS of the accelerator pedal according to thetip-in and the tip-in speed (%/sec) at a step S105.

The second condition is satisfied when the positional change ΔAPS of theaccelerator pedal according to the tip-in is greater than or equal tothe predetermined first positional change (e.g., 10%) and the tip-inspeed (%/sec) is faster than or equal to the predetermined speed.

The predetermined speed may be 53%/sec but can be changed according tovehicle models and design scheme.

If the positional change ΔAPS of the accelerator pedal according to thetip-in and the tip-in speed (%/sec) does not satisfy the secondcondition at the step S105, the control portion 200 performs aconventional shift control (a shift control using the first shiftpattern map) at a step S111, and returns to the step S103.

If the positional change ΔAPS of the accelerator pedal according to thetip-in and the tip-in speed (%/sec) satisfy the second condition at thestep S105, the control portion 200 determines the virtual positionalchange VAPS of the accelerator pedal according to the positional changeΔAPS of the accelerator pedal and the tip-in speed (%/sec) containingacceleration intention by using the map stored in the memory portion 300at a step S106.

After that, the control portion 200 determines the target shift-speed byusing the second shift pattern map according to the virtual positionalchange VAPS of the accelerator pedal stored in the memory portion 300and controls downshift through the actuator 400 at a step S 107.Therefore, acceleration responsiveness may be improved.

At this time, the control portion 200 limits the virtual positionalchange VAPS of the accelerator pedal determined according to thepositional change ΔAPS of the accelerator pedal and the tip-in speed(%/sec) so as not to exceed the actual positional change ΔAPS of theaccelerator pedal by the limiting amount (%).

The limiting amount may be 35% but can be changed according to designscheme.

As described above, in a state that the downshift is controlled by usingthe virtual positional change VAPS of the accelerator pedal determinedbased on the positional change ΔAPS of the accelerator pedal and thetip-in speed (%/sec), the control portion 200 determines whether thepredetermined release condition is satisfied at a step S108.

The release condition is satisfied when the positional change ΔAPS ofthe accelerator pedal is smaller than or equal to the predeterminedsecond positional change (e.g., 10%), the predetermined time has passedafter downshift by using the virtual positional change VAPS of theaccelerator pedal is completed, or the predetermined shift-speed isengaged.

If the release condition is satisfied at the step S108, the controlportion 200 determines the target shift-speed based on the actualpositional change ΔAPS of the accelerator pedal and the driving speed byusing the first shift pattern map stored in the memory portion 300 at astep S109. After that, the control portion 200 controls a shift to thetarget shift-speed through the actuator 400 at a step S110. The firstshift pattern map is a conventional shift pattern map, and fuel economymay be improved by using the first shift pattern map.

FIG. 4 and FIG. 5 are graphs for showing shift states when a virtualpositional change of an accelerator pedal is applied to a control methodfor an automatic transmission according to an exemplary embodiment ofthe present invention.

In a state that the vehicle runs with an eighth forward speed, thepositional change ΔAPS of the accelerator pedal according to the tip-inis 22% and the tip-in speed is 224%/sec, as shown in FIG. 4. In thiscase, sudden tip-in occurs and it is determined that the driver wants toaccelerate quickly.

Therefore, the virtual positional change VAPS of the accelerator pedalis determined according to the positional change of the acceleratorpedal (22%) and the tip-in speed (224%/sec) by using the map stored inthe memory portion 300.

At this time, the virtual positional change VAPS of the acceleratorpedal, as shown in FIG. 4, is determined to be about 32% that is higherthan the actual positional change ΔAPS of the accelerator pedal by 10%.

In this case, the target shift-speed determined according to the virtualpositional change VAPS of the accelerator pedal and the driving speed isa fifth forward speed.

That is, if the positional change ΔAPS of the accelerator pedal is 22%and the tip-in speed is 224%/sec in a state of the eighth forward speed,the control portion 200 controls the downshift from the eighth forwardspeed to the fifth forward speed.

Therefore, acceleration responsiveness may be improved due to increaseof engine output N_(E) according to the positional change of theaccelerator pedal and increase of turbine speed N_(T) according to thedownshift.

If the release condition is satisfied in a state that the shift iscontrolled by using the virtual positional change VAPS of theaccelerator pedal, the control portion 200 uses the first shift patternmap. That is, the shift to the target shift-speed according to theactual positional change of the accelerator pedal and the driving speedis controlled.

In this case, the shift-speed is heightened in a sequence of fifthforward speed→sixth forward speed→seventh forward speed→eighth forwardspeed. Since the shift is controlled according to the first shiftpattern map, fuel economy may be improved.

If the positional change ΔAPS of the accelerator pedal is 18% and thetip-in speed is 145%/sec at this state, sudden tip-in occurs and it isdetermined that the driver wants to accelerate quickly.

Therefore, the virtual positional change VAPS of the accelerator pedalis determined according to the positional change of the acceleratorpedal (18%) and the tip-in speed (145%/sec) by using the map stored inthe memory portion 300.

At this time, the virtual positional change VAPS of the acceleratorpedal, as shown in FIG. 4, is determined to be about 22% that is higherthan the actual positional change ΔAPS of the accelerator pedal by 4%.

In this case, the target shift-speed determined according to the virtualpositional change VAPS of the accelerator pedal and the driving speed isa sixth forward speed.

That is, if the positional change ΔAPS of the accelerator pedal is 18%and the tip-in speed is 145%/sec in a state of the eighth forward speed,the control portion 200 controls downshift from the eighth forward speedto the sixth forward speed.

Therefore, acceleration responsiveness may be improved due to increaseof engine output N_(E) according to the positional change of theaccelerator pedal and increase of turbine speed N_(T) according to thedownshift.

If the release condition is satisfied in a state that the shift iscontrolled by using the virtual positional change VAPS of theaccelerator pedal (not shown in FIG. 4), the control portion 200 usesthe first shift pattern map. In this case, the shift-speed is heightenedin a sequence of sixth forward speed→seventh forward speed→eighthforward speed. Therefore, fuel economy may be improved.

In a state that the vehicle runs with the fifth forward speed, thepositional change ΔAPS of the accelerator pedal is 22% and the tip-inspeed is 52%/sec that is smaller than the predetermined speed, as shownin FIG. 5. In this case, it is determined that the driver does not wantto accelerate quickly and the fifth forward speed that is the currentshift-speed is maintained.

According to an exemplary embodiment of the present invention,acceleration intention of the driver is determined according to thetip-in speed of the accelerator pedal and the shift control is performedby reflecting the acceleration intention of the driver. Therefore,acceleration responsiveness may be improved. In addition, reliability ofthe automatic transmission vehicle may be provided.

In addition, the virtual positional change of the accelerator pedalcontaining the acceleration intention is determined based on thepositional change of the accelerator pedal and the tip-in speed, and thedownshift to the target shift-speed according to the virtual positionalchange of the accelerator pedal is performed. Therefore, quickacceleration responsiveness may be provided due to increase in theengine output and low gear ratio.

Because quick acceleration or slow acceleration is determined based onthe positional change of the accelerator pedal and the tip-in speed anddifferent shift-speeds are engaged according to the quick accelerationor the slow acceleration, different acceleration responsiveness can beprovided at the same positional change of the accelerator pedal.

Because the conventional shift control is performed after theacceleration responsiveness is provided by using the virtual positionalchange of the accelerator pedal containing the acceleration intention,fuel economy may be enhanced.

The foregoing descriptions of specific exemplary embodiments of thepresent invention have been presented for purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteachings. The exemplary embodiments were chosen and described in orderto explain certain principles of the invention and their practicalapplication, to thereby enable others skilled in the art to make andutilize various exemplary embodiments of the present invention, as wellas various alternatives and modifications thereof. It is intended thatthe scope of the invention be defined by the Claims appended hereto andtheir equivalents.

What is claimed is:
 1. A control system for an automatic transmission,including: a detecting portion of detecting a driving informationincluding a temperature of an engine coolant, a temperature of atransmission oil, a positional change of an accelerator pedal, a currentshift-speed, and a driving speed; a control portion determining avirtual positional change of the accelerator pedal based on an actualpositional change of the accelerator pedal and a tip-in speedtransmitted from the detecting portion, to determine a targetshift-speed according to the actual positional change of the acceleratorpedal or the virtual positional change of the accelerator pedal and thedriving speed, and to control a shift to the target shift-speed; and anactuator engaging the target shift-speed according to a control signalreceived from the control portion.
 2. The control system of claim 1,further including a memory portion storing a map in which the virtualpositional change of the accelerator pedal according to the actualpositional change of the accelerator pedal and the tip-in speed is set,a first shift pattern map in which the target shift-speed according tothe actual positional change of the accelerator pedal and the drivingspeed is set, and a second shift pattern map in which the targetshift-speed according to the virtual positional change of theaccelerator pedal and the driving speed is set.
 3. The control system ofclaim 2, wherein the control portion detects the actual positionalchange of the accelerator pedal and the tip-in speed when thetemperature of the engine coolant exists within a predetermined firsttemperature range, the temperature of the transmission oil exists withina predetermined second temperature range, and the current shift-speed ishigher than or equal to a third forward speed.
 4. The control system ofclaim 3, wherein the control portion performs a shift control byapplying the second shift pattern map when the actual positional changeof the accelerator pedal due to tip-in is greater than or equal to apredetermined first positional change and the tip-in speed is fasterthan or equal to a predetermined speed.
 5. The control system of claim3, wherein the control portion performs a shift control by applying thefirst shift pattern map when the actual positional change of theaccelerator pedal due to tip-in is smaller than a predetermined firstpositional change or the tip-in speed is slower than a predeterminedspeed.
 6. The control system of claim 4, wherein the control portion isadapted to downshift to the target shift-speed so as to improveacceleration responsiveness due to a high engine output and a low gearratio when the shift is controlled by applying the second shift patternmap.
 7. The control system of claim 2, wherein the control portion isadapted to limit the virtual positional change of the accelerator pedalaccording to the actual positional change of the accelerator pedal andthe tip-in speed such that the virtual positional change of theaccelerator pedal does not exceed the actual positional change of theaccelerator pedal by a limiting amount.
 8. The control system of claim4, wherein the control portion is adapted to perform the shift controlby applying the first shift pattern map when a predetermined releasecondition is satisfied in a state of performing the shift control byapplying the second shift pattern map.
 9. The control system of claim 8,wherein the predetermined release condition is satisfied when the actualpositional change of the accelerator pedal is smaller than or equal to apredetermined second positional change, a predetermined time has passedafter downshifting to the target shift-speed, or a predeterminedshift-speed is engaged.
 10. A control method for an automatictransmission, comprising: determining whether a first condition issatisfied from a driving information; determining, when the firstcondition is satisfied, whether an actual positional change of anaccelerator pedal due to tip-in and a tip-in speed satisfies a secondcondition; determining a virtual positional change of the acceleratorpedal according to the actual positional change of the accelerator pedaland the tip-in speed when the second condition is satisfied; determininga target shift-speed according to the virtual positional change of theaccelerator pedal and a driving speed; and controlling a shift to thetarget shift-speed according to the virtual positional change of theaccelerator pedal and the driving speed.
 11. The control method of claim10, wherein, when a predetermined release condition is satisfied in astate of controlling the shift to the target shift-speed according tothe virtual positional change of the accelerator pedal and the drivingspeed, a shift to the target shift-speed according to the actualpositional change of the accelerator pedal and the driving speed iscontrolled.
 12. The control method of claim 10, wherein the firstcondition is satisfied when a coolant temperature exists within apredetermined first temperature range, an oil temperature of theautomatic transmission exists within a predetermined second temperaturerange, and a current shift-speed is higher than or equal to a thirdforward speed.
 13. The control method of claim 10, wherein the secondcondition is satisfied when the actual positional change of theaccelerator pedal due to the tip-in is greater than or equal to apredetermined first positional change and the tip-in speed is fasterthan or equal to a predetermined speed.
 14. The control method of claim10, wherein the target shift-speed according to the virtual positionalchange of the accelerator pedal and the driving speed is determined tobe a lower shift-speed than the current shift-speed.
 15. The controlmethod of claim 10, wherein the virtual positional change of theaccelerator pedal determined based on the actual positional change ofthe accelerator pedal and the tip-in speed does not exceed the actualpositional change of the accelerator pedal by a limiting amount.
 16. Thecontrol method of claim 11, wherein the predetermined release conditionis satisfied when the actual positional change of the accelerator pedalis smaller than or equal to a predetermined second positional change, apredetermined time has passed after shifting to the target shift-speedaccording to the virtual positional change of the accelerator pedal andthe driving speed, or a predetermined shift-speed is engaged.
 17. Acontrol system for an automatic transmission, including: a detectingportion adapted to detect a driving information including a temperatureof an engine coolant, a temperature of a transmission oil, a positionalchange of an accelerator pedal, a current shift-speed, and a drivingspeed; and a control portion adapted to control a shift of the automatictransmission based on the driving information detected by the detectingportion, wherein the control portion determines whether a shift controlis possible, and selectively performs fuel economy-oriented shiftcontrol according to an actual positional change of the acceleratorpedal and the driving speed or acceleration-oriented shift controlaccording to a virtual positional change of the accelerator pedal andthe driving speed when the shift control is possible.
 18. The controlsystem of claim 17, wherein the virtual positional change of theaccelerator pedal is determined according to the actual positionalchange of the accelerator pedal and a tip-in speed.
 19. The controlsystem of claim 18, wherein the virtual positional change of theaccelerator pedal does not exceed the actual positional change of theaccelerator pedal by a limiting amount.
 20. The control system of claim17, wherein the control portion is adapted to perform the fueleconomy-oriented shift control when a predetermined release condition issatisfied in a state of performing the acceleration-oriented shiftcontrol.